Sesquialkoxide von Gallium und Indium

Sesquialkoxides of Gallium and Indium Treatment of GaMe₃ with one equivalent of HO^cHex in toluene at 20 °C leads to [Me₂GaO^cHex]₂ ( 4 ) under evolution of methane. The reaction of InMe₃ with two equivalents of HO^cHex leads under similar conditions not to [MeIn(O^cHex)₂]_n but to the sesquialkoxide [In{Me₂In(O^cHex)₂}₃] ( 5 ). 5 can be described also as [{Me₂InO^cHex)}₂{MeIn(O^cHex)₂}₂]. The use of an excess of cyclohexanol in boiling toluene gives the same result. Under these reflux conditions, the reaction of GaMe₃ with an excess of PhCH₂OH leads exclusively to another type of sequialkoxides, [Ga{MeGa(OCH₂Ph)₃}₃] ( 6 ). 4 — 6 were characterized by NMR, vibrational and MS spectra, as well as by X‐ray structure determinations. According to this, 4 forms centrosymmetrical and therefore planar Ga₂O₂ four‐membered rings. 5 and 6 possess basically the same structural motif, central M³⁺ ion ( 5 : In³⁺; 6 : Ga³⁺) coordinated by three metalate units ( 5 : [Me₂In(O^cHex)₂]^—; 6 : [MeGa(OCH₂Ph)₃]^—). The central M³⁺ ions have always coordination number (CN) six while the three surrounding metal ions possess CN 4. Because of the spectroscopic findings 6 must exist in two isomers (1:1). The C₃‐symmetrical isomer C₃‐ 6 was characterized by X‐ray analysis, while the isomer C₁‐ 6 could by described mainly by the complex NMR data.     

Neue Hypersilanide der Erdmetalle Aluminium,Gallium und Indium

New Hypersilanides of the Earth Metals Aluminium, Gallium, and Indium The dialkylaluminiumchlorides R₂AlCl (with R = Me, Et; Me = CH₃, Et = C₂H₅) react with base‐free lithium‐tris(trimethylsilyl)silanide (Li–Hsi; Hsi = –Si(SiMe₃)₃), forming the pyrophoric dialkyl aluminiumhypersilanides R₂Al–Hsi. The methyl compound is dimeric in solid state (triclinic space group P1, Z = 1 dimer), as in Al₂Me₆ the association takes place by two Al–Me–Al bridges, forming a centrosymmetric molecule of approximately C_2h point‐symmetry. Contrary to this (Me₂GaCl)₂ and Li–Hsi form a mixture of (MeGa(Hsi)Cl)₂ and [Me₃Ga–Hsi]Li. The monochloride again is a centrosymmetric, chlorine‐bridged dimer (monoclinic space group P2₁/n, Z = 2 dimers). The extremely air sensitive gallate can be prepared from GaMe₃ and Li–Hsi (1 : 1 ratio), as well as the homologous [Me₃Ga–Hsi]Na and [Me₃Ga–Hsi]K from GaMe₃ and the corresponding alkalimetal hypersilanides. The 1 : 1 toluene‐solvat of the sodium salt crystallizes in the orthorhombic space group Pbca (Z = 8) with polymeric zig‐zag‐chains, in which the toluene‐capped Na‐ions act as GaMe…Na…Me₂Ga‐bridges between [Me₃Ga–Hsi]^– anions. The reaction of InCl₃ with Li–Hsi (1 : 3 ratio) mainly gives LiCl, metallic In and the “dihypersilyl” Hsi–Hsi. Ruby‐red (Hsi)₂In–In(Hsi)₂ could also be obtained in low yield and characterized by X‐ray structure elucidation (space group P2₁/c, Z = 4). The ¹H, ¹³C, ²⁹Si and ⁷Li NMR‐ and the vibrational spectra of the hypersilanides have been measured and discussed.     

Organometallic Diaza‐dimetalla‐Norbornanes and ‐Cyclohexanes of Aluminium,Gallium and Indium

Selective formation of 1,3,3,4,6,6‐hexamethyl‐1,4‐diaza‐3,6‐diinda‐norborane was achieved by the reaction of bis(lithiomethyl‐methylamino)methane with dimethylindium chloride by simultaneous formation of two dative metal‐carbon and two metal‐nitrogen bonds accompanied by two ring closures. The synthesis of heterometallic compounds of this type, namely 1,3,3,4,6,6‐hexamethyl‐3‐alumina‐1,4‐diaza‐6‐galla‐norborane [Me₂AlCH₂N(Me)]CH₂[N(Me)CH₂GaMe₂], was also attempted by the reaction of bis(lithiomethyl‐methylamino)methane with dimethylaluminium and ‐gallium chloride. This compound is formed, but cannot be separated from the simultaneously formed homometallic compounds [Me₂MCH₂N(Me)]₂CH₂(M = Al, Ga). The compounds were identified by elemental analyses, mass spectra, NMR spectroscopy (¹H, ¹³C), and by determination of their crystal structures in which they are present as monomers. The norbornane‐like structure is favoured over potential isomers containing three‐membered rings and over polymeric aggregation in both compounds. In addition, the crystal structure of dimethyl(dimethylaminomethyl)indium was determined by single crystal X‐ray diffraction, which shows an intermolecular aggregation into a six‐membered ring dimer.     

Synthese und Charakterisierung von InIII–SnII‐Halogenido‐Alkoxiden und von Indiumtri‐tert‐butoxid

Synthesis and Characterization of In^III–Sn^II‐Halogenido‐Alkoxides and of Indiumtri‐ tert ‐butoxide Through sodium halide elimination between Indium(III) halides and sodium‐tri‐tert‐butoxistannate(II) or sodium‐tri‐tert‐butoxigermanate(II) the three new heterometallic and heteroleptic alkoxo compounds THF · Cl₂In(OtBu)₃Sn ( 1 ), THF · Br₂In(OtBu)₃Sn ( 2 ), and THF · Cl₂In‐ (OtBu)₃Ge ( 3 ), have been synthesized. The molecular structures of 1 and 2 in the solid state follow from single crystal X‐ray structure determinations while structural changes in solution may be derived from temperature dependant NMR spectroscopy. The crystal structures of compounds 1 and 2 are despite different halide atoms isostructural. Both crystallize in the ortho‐rhombic crystal system in space group Pbca with eight molecules per unit cell. The heavy atoms occupy the apical positions of empty trigonal bipyramids of almost point symmetry C_s(m) and are connected through oxygen atoms occupying the equatorial positions. The indium atoms in both compounds are in the centers of distorted octahedra from 4 oxygen and 2 halogen atoms whereas the tin atoms are coordinated by three oxygen atoms in a trigonal pyramidal fashion. Although the coordinative bonding of THF to indium leads to an asymmetry of the molecule the NMR spectra in solution are simple showing a more complex pattern at lower temperatures. Tri(tert‐butoxi)indium [In(OtBu)₃]₂ ( 4 ), is obtained through alcoholysis of In(N(Si(CH₃)₃)₂)₃ using tert‐butanol in toluene and is crystallized from hexane. The X‐ray structure determination of 4 seems to be the first one of a homoleptic and homometallic indiumalkoxide. Compound 4 crystallizes in the monoclinic crystal system in a dimeric form with eight molecules in the unit cell of space group C2/c. The dimeric units have C₂ symmetry and an almost planar In₂O₂ ring which originates from oxygen bridging of the monomers. Through this mutual Lewis acid base interaction the indium atoms get four oxygen ligands in a distorted tetrahedral environment.     

Dimethylerdmetall‐Heterocyclen als Derivate trimethylsilylierter, ‐germylierter und ‐stannylierter Phosphane und Arsane – Synthesen,Spektren und Strukturen

Dimethyl Earth‐Metal Heterocycles – Derivatives of Trimethyl‐silylated, ‐germylated, and ‐stannylated Phosphanes and Arsanes – Syntheses, Spectra, and Structures The organo earth‐metal heterocycles [Me₂M^III–E(M^IVMe₃)₂]_n with M^III = Al, Ga, In; E = P, As; M^IV = Si, Ge, Sn and n = 2, 3 (Me = CH₃) have been prepared from the dimethyl metal compounds Me₂M^IIIX (X = Me, H, Cl, OMe, OPh) and the pnicogen derivatives H_nE(M^IVMe₃)_3–n (n = 0, 1) according to known preparation methods. The mass, ¹H, ¹³C, ³¹P, ²⁹Si, ¹¹⁹Sn nmr, as well as the ir and Raman spectra have been discussed comparatively; selected representatives are characterized by X‐ray structure analyses. The dimeric species with four‐membered (E–M^III)₂ rings are isotypic and crystallize in the triclinic space group P1, the trimer [Me₂In–P(SnMe₃)₂]₃ with a strongly puckered (In–P)₃‐ring skeleton crystallizes with two formula units per cell in the same centrosymmetric triclinic space group.     

Gallium and Indium Arsanido Metalates: Compounds Derived from the Zinc Blende and Wurtzite Structure

The reaction of InCl₃ with LiAs^tBu₂ in THF at –78 °C gives the indium arsenide Cl₂InAs^tBu₂ ( 1 ), which is dimer in solution and solid state. The corresponding reaction of InCl₃ with Li₂As^tBu leads to the metalate [Li(THF)₄]₂[(InCl)₄(InCl₂)₂(As^tBu)₆] ( 2 ). The arsanido metalate [Li(THF)₄]₂[(GaCl₂)₆(As^tBu)₄] · THF ( 3 · THF) could be obtained by treatment of GaCl₃ with Li₂As^tBu in the molar ratio 6 : 4. A comparable reaction with TlCl₃ and LiAsR₂ or LiPR₂, respectively, was not successful because of the oxidation potential of TlCl₃. The reaction mixture of TlCl₃ and LiPPh₂ for example gives TlCl and Ph₂P–PPh₂ ( 4 ) as redox products. The octaarsane [As(As^tBu)₃]₂ ( 5 ) can be obtained by the treatment of ^tBuAs(SiMe₃)₂ with TlCl₃ in THF. 1–5 were characterized by NMR, IR and MS techniques. The X‐ray analyses of 2 and 3 · THF show that 2 can be derived from the wurtzite structure while the zinc blende structure is the model for 3 with a adamantane‐like dianion [(GaCl₂)₆(As^tBu)₄]^2–.     

Synthesis and Crystal Structures of Aluminum,Gallium and Indium Complexes with Chelating Me2Si(NPh)22– Ligands

The reaction of ECl₃ (E = Al, Ga) with two equivalentsof Li₂Me₂Si(NPh)₂ (in diethyl ether/n‐hexane) leads to the formation of bis‐chelate complexes [Li(OEt₂)₃][E{Me₂Si(NPh)₂}₂] (E = Al ( 1 ), Ga ( 2 )). Compounds 1 and 2 crystallize isotypically in the monoclinic system with a = 1136.42(6), b = 3267.9(1), c = 1360.37(8) pm, β = 94.320(7)° for 1 and a = 1140.88(6), b = 3261.7(2), c = 1360.20(8) pm, β = 94.641(7)° for 2 . Both the compounds display a distorted tetrahedral coordination of the central metal atom to give a spirocyclic EN₄Si₂ core. The Al–N bond lengths are in the range of186.5–186.9 pm and for the Ga–N distances values between 192.3and 193.1 pm are observed. Treatment of InCl₃ with three equivalents of Li₂Me₂Si(NPh)₂ yields the tris‐chelate [{Li(OEt₂)}₃In{Me₂Si(NPh₂)}₃] 3 . Compound 3 crystallizes in the trigonal crystal system , space group R$\bar{3}$ c with a = 1852.4(1), and c = 3300.2(2) pm. The central indium atom is coordinated by threeMe₂Si(NPh)₂^2– ligands in a distorted octahedral arrangement withIn–N bond lengths of 230.8 pm.     

Chirale Gallium‐ und Indium‐Alkoxometallate

Chiral Gallium and Indium Alkoxometalates Li₂(S)‐BINOLate ((S)‐BINOL = (S)‐(–)‐2,2′‐Dihydroxy‐1,1′‐binaphthyl) generated by dilithiation of (S)BINOL with two equivalents ⁿBuLi was reacted with GaCl₃ und InCl₃ in THF to the alkoxometalates [{Li(THF)₂}{Li(THF)}₂{Ga((S)‐BINOLate)₃}] ( 1 ) and [{Li(THF)₂}₂{Li(THF)}{In((S)‐BINOLate)₃}] · [{Li(THF)₂}{Li(THF)}₂{In((S)‐ BINOLate)₃}]₂ ( 3 ), respectively. 1 and 3 crystallize from THF/toluene mixtures as 1 · 2 toluene and 3 · 8 toluene. The treatment of PhCH₂GaCl₂ with Li₂(S)‐BINOLate in THF under reflux, followed by recrystallization of the product from DME gives the gallate [{Li(DME)}₃{Ga((S)BINOLate)₃}] · 1.5 THF ( 2 · 1.5 THF). 1 – 3 were characterized by NMR, IR and MS techniques. In addition, 1 · 2 toluene, 2 · 1.5 THF and 3 · 8 toluene were investigated by X‐ray structure analyses. According to them, a distorted octahedral coordination sphere around the group 13 metal was formed, built‐up by three BINOLate ligands. The three Li⁺ counter ions act as bridging units by metal‐oxygen coordination. The coordination sphere of the Li⁺ ions was completed, depending on the available space, by one or two THF ligands ( 1 · 2 toluene, 3 · 8 toluene) and one DME ligand ( 2 · 1.5 THF), respectively. The sterical dominance of the BINOLate ligands can be shown by the almost square‐planar coordination of the Li⁺ ions in 2 · 1.5 THF giving a small twisting angle of only 17°.     

[PtIn6][GaO4]2 – das erste Oxid mit [PtIn6]‐Oktaedern. Darstellung,Charakterisierung und Rietveldverfeinerung – mit einer Bemerkung zur Mischkristallreihe [PtIn6][GaO4]2–x[InO4]x (0 < x ≤ 1)

[PtIn₆][GaO₄]₂ – The First Oxide Containing [PtIn₆] Octahedra. Preparation, Characterisation, and Rietveld Refinement – With a Remark to the Solid Solution Series [PtIn₆][GaO₄]_2‐x[InO₄]_x (0 < x ≤ 1) The novel oxides [PtIn₆][GaO₄]_2–x[InO₄]_x (0 < x ≤ 1) are formed by heating intimate mixtures of Pt, In, In₂O₃, and Ga₂O₃ in the corresponding stoichiometric ratio in corundum crucibles under an atmosphere of argon (1220 K, 70 h). The compounds are black, stable in air at room temperature, reveal a semiconducting behaviour, and decompose only in oxidizing acids. X‐ray powder diffraction patterns can be indexed by assuming a face centered cubic unit cell with lattice parameters ranging from a = 1001.3(1) pm (x = 0) to a = 1009.3(1) pm (x = 1). According to a Rietveld refinement [PtIn₆][GaO₄]₂ crystallizes isotypic to the mineral Pentlandite (Fm3m, Z = 4, R(profile) = 6.11%, R(intensity) = 3.95%). The characteristic building units are isolated [PtIn₆]¹⁰⁺ octahedra which are linked via [GaO₄]^5– tetrahedra to a three dimensional framework. Starting from [PtIn₆][GaO₄]₂ the substitution of Ga³⁺ ions by larger In³⁺ ions leads to the formation of a solid solution series according to the general formula [PtIn₆][GaO₄]_2–x[InO₄]_x and becomes apparent in an increase of the lattice parameter.     

Kristallstrukturen von TMEDA‐Addukten und Salzen mit protonierten TMEDA‐Molekülen

Crystal Structures of TMEDA Adducts and of Salts with Protonated TMEDA Molecules The reaction of TMEDA with two equivalents of [BH₃(SMe₂)] in toluene at 20 °C gives the adduct [TMEDA(BH₃)₂] ( 1 ). A similar reaction of pyrrolidine with [BH₃(SMe₂)] in a molar ratio of 1:1 leads to the adduct [pyrrolidine(BH₃)] ( 2 ). TMEDA can be introduced into the coordination sphere of In³⁺ by the treatment of InI₃ with TMEDA in toluene to give the complex [InI(TMEDA)] ( 3 ). The salt [HTMEDA]I ( 4 ), containing a mono‐protonated TMEDA molecule, is the result of the reprotonation of [NH₄]I and TMEDA in toluene at 20 °C. The salts [H₂TMEDA]—[InCl₄(TMEDA)]₂ ( 5 ) and [H₂TMEDA][InCl₅(THF)] ( 6 ) are formed in the reaction mixtures TMEDA/toluene/InCl₃/HCl and TMEDA/toluene/THF/InCl₃/HCl, respectively, whereupon 6 was characterized more closely. Crystals of [In₅I₆(OH)(TMEDA)₄]I·2, 5toluene ( 7 ·2.5toluene) can be obtained after treatment of InI₃ with non‐dried TMEDA; 4 was identifed as by‐product. 1 — 7 ·2.5toluene were partially investigated by NMR methods and vibrational spectroscopy. In all cases a characterization by single crystal X‐ray diffraction was performed. According to this, all nitrogen atoms in 1 and 2 are coordinated by BH₃ groups leading to a distorted tetrahedral environment at the nitrogen and the boron atoms. In 3 a distorted trigonal‐bipyramidal coordination sphere at the In³⁺ is present. The apical positions are occupied by I3 and N3. Strong N‐H···N bridges, running along [001] is the feature in 4 ; the ^I—‐Ions are not involved into the system of H‐bridges. A ion triple, [H₂TMEDA][InCl₄(TMEDA)]₂, hold together by bifurcated H‐bridges is the dominating structural motif in 5 , whereas alternation bifurcated and linear H‐bridges, leading zu a zig‐zag chain along [100], is the build‐up principle of 6 . In 7 ·2.5toluene a complex In₅O₈ skeleton was formed, consisting of a virtual corner‐connected doubled heterocubane. At every heterocubane a corner, occupied by a metal ion, is missing. The coordination spheres of the In atoms of the complex cation are completed by TMEDA molecules and iodide ions.     

Reaktion von (R,R)‐(N,N′)‐Diisopropylcyclohexyl‐1,2‐diamin mit Me2MCl (M = Ga,In)

Reaction of (R,R)‐(N,N′)‐Diisopropylcyclohexyl‐1,2‐diamine with Me₂MCl (M = Ga, In) (R,R)‐(N,N′)‐Diisopropylcyclohexyl‐1,2‐diamine (H₂L) was reacted with Me₂GaCl and Me₂InCl in boiling toluene, respectively. In both cases the salt [Me₂M(H₂L)][Me₂MCl₂] [M = Ga ( 1 ), In ( 2 )] was formed. 1 and 2 were characterized by NMR and vibrational spectroscopy. In addition, an X‐ray structure determination was applied on 2 . According to the spectroscopical and structural findings 1 and 2 consist of cations [Me₂M(H₂L)]⁺ and anions [Me₂MCl₂]^?.     

1‐Aminoindan‐2‐ol,a Suitable Ligand for the Synthesis of Chiral,Intramolecularly Stabilized Compounds of Aluminum,Gallium, and Indium

The reactions of enantiomerically pure (1R, 2S)‐(+)‐cis‐1‐aminoindan‐2‐ol, (1S, 2R)‐(‐)‐cis‐1‐aminoindan‐2‐ol, and racemic trans‐1‐aminoindan‐2‐ol with trimethylaluminum, ‐gallium, and ‐indium produce the intramolecularly stabilized, enantiomerically pure dimethylmetal‐1‐amino‐2‐indanolates (1R, 2S)‐(+)‐cis‐Me₂AlO‐2‐C*HC₇H₆‐1‐C*HNH₂ ( 1 ), (1S, 2R)‐(‐)‐cis‐Me₂AlO‐2C*HC₇H₆‐1‐C*HNH₂ ( 2 ), (1R, 2S)‐(+)‐cis‐Me₂GaO‐2‐C*HC₇H₆‐1‐C*HNH₂ ( 3 ), (1R, 2S)‐(+)‐cis‐Me₂InO‐2‐C*HC₇H₆‐1‐C*HNH₂ ( 4 ), (1S, 2R)‐(‐)‐cis‐Me₂InO‐2‐C*HC₇H₆‐1‐C*HNH₂ ( 5 ), and racemic (+/‐)‐trans‐Me₂InO‐2‐C*HC₇H₆‐1‐C*HNH₂ ( 6 ). The compounds were characterized by ¹H NMR, ¹³C NMR, ²⁷Al NMR and mass spectra as well as 1 and 3 to 6 by determination of their crystal and molecular structures. The dynamic dissociation/association behavior of the coordinative metal‐nitrogen bond was studied by low temperature ¹H NMR spectroscopy.     

Die Insertion von Sauerstoffatomen in Ga–Ga- und In–In-Bindungen – Bildung von monomeren Verbindungen R2E–O–ER2 [R = CH(SiMe3)2] mit stark aufgeweiteten E–O–E-Winkeln

The Insertion of Oxygen Atoms into Ga–Ga and In–In Bonds – Formation of the Monomeric Compounds R₂E–O–ER₂ [R = CH(SiMe₃)₂] with Strongly Enlarged Angles E–O–E The tetraalkyldielement compounds R₂Ga–GaR₂ ( 1 ) und R₂In–InR₂ ( 2 ) [R = CH(SiMe₃)₂] reacted with trimethylamine N-oxide by the insertion of oxygen atoms in their element-element single bonds. The products R₂E–O–ER₂ are monomeric in the solid state due to the high steric shielding by the voluminous bis(trimethylsilyl)methyl groups. As shown by crystal structure determinations, the E–O–E bridges have large angles of 142.7 (E = Ga, 3 ) and 138.6° (E = In, 4 ) and short separations between the oxygen and the coordinatively unsaturated Ga and In atoms. Both products are extremely hygroscopic.     

Reaktionen von Lithiumhydridosilylamiden RR′(H)Si–N(Li)R″ mit Chlortrimethylsilan in Tetrahydrofuran und unpolaren Lösungsmitteln: N‐Silylierung und/oder Cyclodisilazanbildung

Reactions of Lithium Hydridosilylamides RR′(H)Si–N(Li)R″ with Chlorotrimethylsilane in Tetrahydrofuran and Nonpolar Solvents: N‐Silylation and/or Formation of Cyclodisilazanes The lithiumhydridosilylamides RR′(H)Si–N(Li)R″ ( 2 a : R = R′ = CHMe₂, R″ = SiMe₃; 2 b : R = R′ = Ph, R″ = SiMe₃; 2 c : R = R′ = CMe₃, R″ = SiMe₃; 2 d : R = R′ = R″ = CMe₃; 2 e : R = Me, R′ = Si(SiMe₃)₃, R″ = CMe₃; 2 f – 2 h : R = R′ = Me, f : R″ = 2,4,6‐Me₃C₆H₂, g : R″ = SiH(CHMe₂)₂, h : R″ = SiH(CMe₃)₂; 2 i : R = R′ = CMe₃, R″ = SiH(CMe₃)₂) were prepared by reaction of the corresponding hydridosilylamines RR′(H)Si–NHR″ 2 a – 2 i with n‐butyllithium in equimolar ratio in n‐hexane. The unknown amines 1 e – 1 i and amides 2 f – 2 i have been characterized spectroscopically. The wave numbers of the Si–H stretching vibrations and ²⁹Si–¹H coupling constants of the amides are less than of the analogous amines. This indicates a higher hydride character for the hydrogen atom of the Si–H group in the amide in comparison to the amines. The ²⁹Si‐NMR chemical shifts lie in the amides at higher field than in the amines. The amides 2 a – 2 c and 2 e – 2 g react with chlorotrimethylsilane in THF to give the corresponding N‐silylation products RR′(H)Si–N(SiMe₃)R″ ( 3 a – 3 c , 3 e – 3 g ) in good yields. In the reaction of 2 i with chlorotrimethylsilane in molar ratio 1 : 2,33 in THF hydrogen‐chlorine exchange takes place and after hydrolytic work up of the reaction mixture [(Me₃C)₂(Cl)Si]₂NH ( 5 a ) is obtained. The reaction of the amides 2 a – 2 c , 2 f and 2 g with chlorotrimethylsilane in m(p)‐xylene and/or n‐hexane affords mixtures of N‐substitution products RR′(H)Si–N(SiMe₃)R″ ( 3 a – 3 c , 3 f , 3 g ) and cyclodisilazanes [RR′Si–NR″]₂ ( 6 a – 6 c , 6 f , 6 g ) as the main products. In case of the reaction of 2 h the cyclodisilazane 6 h was obtained only. 2 c – 2 e show a very low reactivity toward chlorotrimetyhlsilane in m‐xylene and toluene resp.. In contrast to Me₃SiCl the reactivity of 2 d toward Me₃SiOSO₂CF₃ and Me₂(H)SiCl is significant higher. 2 d react with Me₃SiOSO₂CF₃ and Me₂(H)SiCl in n‐hexane under N‐silylation to give RR′(H)Si–N(SiMe₃)R″ ( 3 d ) and RR′(H)Si–N(SiHMe₂)R″ ( 3 d ′) resp. The crystal structures of [Me₂Si–NSiMe₃]₂ ( I ) ( 6 f , 6 g and 6 h ) have been determined.     

Darstellung,Eigenschaften und Molekülstrukturen von Dimethylmetallalkoxiden und ‐amiden des Aluminiums und Galliums

Preparation, Properties, and Molecular Structures of Dimethylmetal Alkoxides and Amides of Aluminium and Gallium Dimethylaluminium‐ ( 1 ) and Dimethylgallium‐o‐methoxyphenyl‐1‐ethoxide ( 2 ) were obtained by reaction of Me₃Al and Me₃Ga respectively with o‐Methoxyphenyl‐1‐ethanol in n‐pentane. Dimethylaluminium‐ ( 3 ) and dimethylgallium‐o‐methoxyphenyl‐2‐ethylamide ( 4 ) were prepared by treatment of Me₂AlCl and Me₂GaCl respectively with Lithium‐o‐methoxyphenyl‐2‐ethylamide. Trimethylgallium‐o‐methoxyphenylmethylamine‐Adduct ( 5 ) was isolated using reaction of Me₃Ga with the corresponding amine. The compounds were characterised by ¹H‐, ¹³C‐, and ²⁷Al n.m.r. spectroscopy. The molecular structures of 2 and 5 were determined by X‐ray diffraction. Compounds 1 – 4 form brigded dimeric molecules. The bond distances of the central Ga₂O₂ ring in 2 correspond to those of compounds of similar structure.